Energy conservation and protection from noxious air contaminants represents two divergent goals for a conditioned air environment, that is prewarmed air for cold climates and precooled for warm climates. The use of large amounts of make-up air through an exhaust system can effectively sweep the temperature controlled area free from air contaminants. However, the use of such energy conditioned air in large quantities inevitably results in untoward and expensive energy usage.
The use of totally enclosed hoods which limit the availability of accessible work area and the ability to observe what occurs therewithin, while effectively controlling the dispersion of noxious fumes, does not lend itself to adequate or desirable supervision when untrained students are conducting those chemical experiments which are so necessary to the learning process.
The present invention provides the educational laboratory with good visual observation, minimal energy requirements, plus effective air and fume control, all of which are essential to teaching the laboratory arts, especially chemistry. It accomplishes these goals by providing make-up air which is used primarily as the carrier fluid for said noxious fumes and particulates, thus avoiding the use of large volumes of expensive temperature controlled air. In moderate climates, outside air can be used directly. In severe climates, the outdoor air should be tempered before use.
The extraction of noxious gases and fumes takes place near the bench top, thus affording the most efficient use of the air induction/partial pressure air removal that is easily adjustable to prevent unwanted currents or drafts, even at low air induction volumes.